Struct LossController 

pub struct LossController { /* private fields */ }

Loss-based congestion control, per draft-ietf-rmcat-gcc-02 §5.5.

Why delay is not enough

A path can drop packets without ever queueing them — a wireless link with interference, or a bottleneck whose buffer is so shallow that it overflows before the delay signal moves. The delay-based half sees nothing there, so without this a sender keeps pushing into a link that is discarding a tenth of what it sends.

Between the two thresholds nothing happens. That band is deliberate: a few per cent loss is normal on a wireless link and reacting to it would give up capacity permanently.

Divergence from upstream (D4)

This controller may move the target on its own. Upstream’s cannot: its latestBitrate is only written inside onDelayUpdate (send_side_bwe.go:304), so on a lossy link without queueing delay its loss estimate is computed and then never applied — exactly the case this exists for. That is a bug rather than a design choice, and it is not inherited.

Implementations

impl LossController

pub fn new(initial: f64, min: f64, max: f64) -> Self

A controller starting at initial, clamped to min..=max.

pub fn target(&self) -> f64

The current loss-based target, in bits per second.

pub fn average_loss(&self) -> Option<f64>

The smoothed loss fraction, if any feedback has arrived.

pub fn update(&mut self, now: Instant, lost: usize, total: usize) -> f64

Fold in one batch of feedback: lost of total packets did not arrive.

Trait Implementations

impl Clone for LossController

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LossController

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.